Preorganization and cooperativeness of multifunctional groups play a major role in biological reaction kinetics (A. R. Fersht, Trends Biochem. Sci. 28, 3111, 1987). Calix[4]arene is proposed as a promising host molecule due to the directional preorganization of functional binding groups and its capacity to cooperate the guest binding site rapidly by low energy conformational change (T. Harade, J. M. et al., Tetrahedron 49, 5941, 1993; J. Scheerder, et al., Angew. Chem. 108, 1172, 1996; Angew. Chem. Int. Ed. Engl. 35, 1090, 1996). Accordingly, it has been utilized as a building block for multifunctional enzyme models (P. Molenveld, et al., J. Am. Chem. Soc. 120, 6726, 1998). Recently, calix[4]arenes have been coupled with sugars (A. Dondoni, et al., Tetrahedron Lett. 42, 3295, 2001), amico acids (L. Frkanec, et al., Chem. Eur. J. 6, 442, 2000) and peptides (Y. Hamuro, et al., Angew. Chem. 109, 2797, 1997) to develop biologically active synthetic receptors or enzyme mimics. However, modified oligodeoxynucleotides (ODNs) containing calix[4]arene moieties are unprecedented.
The present inventors have endeavored to develop modified ODNs containing calix[4]arene moieties which can function as DNA hairpin structure mimics.